Problem: Christopher starts counting at 37, and he counts by fours. If 37 is the 1st number that Christopher counts. what is the 8th number that he counts?
Explanation: What is the first number that he counts? $37$ What is the second number that he counts? $\begin{align*}&37 + 4 \\ &= 41\end{align*}$ What is the third number that he counts? $\begin{align*}&37 + 4 + 4 \\ &= 37 + (2 \times 4) \\ &= 45\end{align*}$ What is the 8th number that he counts? $\begin{align*}&37 + (7\times4) \\ &= 37 + 28 \\ &= 65\end{align*}$